Brake shoe construction



Z4, 1940. l s SCHNELL 2,215,567

BRAKE SHOE CONSTRUCTION Filed July 13, 1939 2 Sheets-Sheet 2 lun@ Patentedsept. 24, i940 I UNITED sl'llirlls LPlTl-:N'l ol-llcl-:`

.Y y A 2,215,563

Steve Schnell, verland, Mo., assigner to Wagner l Electric Corporation, St. Louis, Mo., a corporation of'Delaware application `July 1s, 193g, sol-lol No. 284,186

11x calms. (c1. lss-1s) My invention relates to braking mechanism and more particularly to an improved brake shoe construction. A u l One of theobiects of my inventionis to produce an improved brake shoe constructionof the pivotedvtype which will permit its heel end to be actuated into engagement with the drum' by a `Wedgillg action and which will also be stable" and controllable during appllcationtrvl and release from the drum and also during braking m action.

Another oblect of my invention is to provide an improved brake shoe and mounting means therefor which will permit the shoe to produce 15 maximum braking action while at the same time allowing theshoe to be actuated into and out of engagement with the. drum by a pivotal movement about a xed axis positioned at the heelr end of the shoe. V A.

Other objects of my invention will become ap- -parent from the following description taken ln connection with the accompanying drawings in which Figuregl is a view of a'brake assembly showing' my improved shoe construction elnbodied therein; Figures 2, 3 and tare crosssectional views showing details and being taken on the lines 2 2.' 31-3 and 4-4 of Figurel; Figure 5 is a view showing a modified construction; Figure 6 is a view of another modiiled con! struction embodying the invention and Figure 'I la a cross-sectionalview taken on the line 1--1 w otli'isuleii.' v

- RefemngtoFIgures1to4indetaiLnumeralI l. The shoe 4 is' the normal reverse shoer of the brake and is pivotally molmted at its heel endtothebackingplatebymeansofanadiustable eccentric anchor pin t .and a bearing sleeve Ippositioned in an opening'in the shoe ,as'iscommon practice.

'me broke shoe a le me normal. "forward" adjustable anchor pin Il oorrylns'fa bearingsleeve II. The width of the arcuate slot is the same as the diameter of the sleeve and, therefore, Y the end ofthe web is prevented from any radial movement toward drumbut because of the leillth of this Mitiapermitted tohave ci1' movement A mmm fiance Il shoe and-is of a special construction embodying extends oversbscantlauy the entire length vor thel web 8 and is secured to the web.' preferably by welding, over that portion of the web between 'an'intermediate point I3 and the toe end of the web which is actuated by the fluid motor 5. The 5 remaining portion of the flange between the point "I3 and the 4pivoted end of the web is free -of the web for movement relative to the web and toward the drum. Since the flange is made Y in the form of a ilat strip,` it has a certain degree 1 of ilexibility and because of this, thel unsecured 'portion of the ange is in eifectA hinged to the secured portion atthe point Il. The ange I2 fis provided with the usual lining I4.

The unsecured portion of the flange' has se- 15 cured thereto, preferably b y welding, a U-shaped reenforcing member I5, the legs of 'which receive the web 8 as iest'shown in Figure 3. -Two plates I6 are mounted on the bearing sleeve Il of the,

anchor pin on opposite sides of the-.web and 20 -each has an edge surface I1 inclined to a radius of the drum. The surfaces .AI'I cooperate with inclined surfaces I8 on thev ends ofthe legs of the reenforcing member vI5 and are maintained in contact by a spring I9, one end of which is 25 hooked vto the reenforcing member and the otherposition by a.` coll spring ,2| connected tothe. shoes and'when in "oil position, sh'oe 4 engages indicates the drum of a brake and 2 the backing Plate secured to Ia xed part of the vehicle. y Withinthedrumaretwo shoes! and4 actuated into engagement with the drum by a`iiuid motor 1 an adjustable stop zz one adjustable stop 23.

shoe rengages an When the drum is rotating in the direction lindicated by the arrow andJ the shoes are -applied to the drum by the iluid motor, shoe 4 willact as an grdlnary revers shoe. Shoe I, when 'brought into engagement with the drum,vwill tend lao-be carried with the drum. slnoetno 4 slot 0 permits the web 4 of the shoe to havecircumferential movement. the shoe will anchor on the backing plate through the member` I5 and the plates I6 on the anchor pin III. 'lhe'force acting on the reenforcing member when the shoe is applied is inr.a ,circumferential direction and since the surfaces Il and Il are positioned at an angle to this direction of. force, a wedging. action will take place which will create an outward radial force o n the free end of the ange l2, thus'causing the lining over that portion of the flange from the point Il to the mounted end oftheshoetobeeullagedwlththedl'ulnwltll greaterlntemitythanwouldbethecaseifthe shoe were of the ordinary pivoted type like shoe 4. It is thus seen that by means of the shoe construction and mounting shown, the heel end portion of the shoe is caused to have a greater braking action and, therefore, the torque output of the shoe is increased. The toe portion of the shoe is not affected by the wedging action since the web is restrained from radial movement toward the drum by the slot 9 'and the anchor pin. There is no possibility of the shoe becoming locked with the drum as would be the case if the web of the shoe were free to move toward the drum at the anchor pin. The shoe is easily controllable and may be readily applied and released from the drum under the action of the fluid motor.

In the modification shown in Figure 5, the U-shaped reenforcing member l5' is shown as pivotally mounted by means of a pin 24 to the web 8 of the shoe. Such a construction permits the lining carrying flange to be made in two pieces, the piece I2 `being secured to the toe portion of the shoe and the piece I2 being secured to the pivoted reenforcing member I5. The operation of the modified brake shoe is the same as shoe 3 shown in Figure 1.

In the,4 modification shown'in Figure 6, the brake shoe comprises a web portion 25 which is formed with an arcuate slot 26 at its lower end for receiving the bearing 21 mounted on the anchor pin 28 secured to the backing plate 29.'

flange and lining carried thereby can have rela-- tive outward movement with respect to the web. In order to obtain a radial force on the web portion 34 when the shoe is applied to the drum and the web is caused to have a circumferential movement, the bearing 21 on the anchor pin has pivotally mounted thereon arms 35 positioned on opposite sides of the web. The ends of the arms carry a pin 3Gl which engages' a surface 31 on the lower end of the web portion 34. Since the arm is at a wedging angle to circumferential force acting on the web when the -shoe is applied, the lever arm will force the web portion 35 and the lining carried thereby outwardly into engagement with the drum. It is thus seen. that the action of the shoe is the same as shoe showninFigure 1.

Being aware of the possibility of other modiications in the particular structure herein described without departing from the fundamental principles of my invention, I do not intend that its scope be limited except as set forth by the appended claims.

Having fully described my invention, *what I claim as new and desire to secure -by Letters Patent of the United States is:

1. In braking mechanism, asupport, a brake drum, a brake shoe for cooperationwith the drum, said shoe comprising a member mounted at one end for -permitting swinging movement of the member toward the drum and also mounted at said end for circumferential movement with the drum but restrained from radial movement toward the drum, Asaid shoe being provided with a drum engaging means which is so secured to the member" that it is free to move relatively to the member a'nd outwardly toward the drum at the mounted end of the member, and means operable by circumferential movement of the member when the shoe is applied to the drum for forcing the free portion of the drum engaging means-toward the drum and relatively to the mounted end of the member.

2. In braking mechanism, a support, a. brake drum, a brake shoe for cooperation with the drum, said shoe comprisinga member mounted at-one end on the support for pivotal movement and for circumferential movement with the drum but restrained from radial movement toward the drum, drum' engaging means secured to the member at a point spaced from the mounted end and capable of circumferential movement with the member but free to move relatively to the member and outwardly toward the drum over the portionpf the member between said point of securement and the pivoted end of the member, and means operable by the circumferential movement of the member when the shoe isapplied to the drum for forcing the drum engaging means toward the drum and relatively to the mounted end of the member.

3. In braking mechanism, a supporta brake drum, an anchor pin on the support, a brake shoe mounted on the anchor pin for cooperation with the drum, said shoe comprising an arcuate member mounted at one endV on the pin for pivotal movement and for circumferential movement with the drum, drum engaging means carried by the member for circumferential movement therewith but. free to move relatively to the member and outwardly toward the drum over at least a portion of the member extending from the pivoted end of the member toward the otherend, and means operable by the circumferential movement of the member when the shoe is applied to the drum for forcing the drum engaging means toward the drum.

4. In braking mechanism, a support, a brake drum, a brake shoe for cooperation with the drum, said shoe comprising an arcuate web mounted at one end on the support for pivotal movement and for circumferential movement 'with the ldrumbutrestrained from-radial movement toward the drum, drum .engaging means hinged to the web at a point circumferentially spaced from the mounted end and free of the web from said point to the mounted end of said web, and means operable by circumferential movementof the webiwhen the shoe is applied to the drum for forcing the drum engaging means toward the drum and relatively to the mounted end of the web.

, 5. In braking mechanism, a. support, a brake drum, a brake shoe for cooperation with the drum, said shoey comprising an arcuate web mounted at one-'end` on the support for pivotal movement and for circumferential movement with the drum but restrained from radial movement toward the drum, a lining carrying flange secured to the web for circumferentialmovement therewith but free of the web for relative outward movementtoward the -drum from an drum, a brake shoe for `cooperation with the" 2,215,567 umm, said shoe comprising a."-.web mounted at one end on the support for pivotal movement and for circumferential movement with the drum but restrained -from radial .movement toward' the drum, a lining carrying flange extending over the major portion of the web and being secured to a portion'of the web from an intermediate point to the free end of the web and so associated with the'remaining portion of the web that it is free to move relatively to the web and outwardly toward the drum, and means operable by circumferential movementl when the shoe is applied to the drum for forcing the free portion of the lining carrying flange toward the drum and relatively to the mounted end of the web.

'1. In braking mechanism, a' support, a brake drum, a brake shoe for cooperation withr the drum, said shoe comprising an arcuate web mounted at one end on the support for pivotal movement and for .circumferential movement with the drum' but restrained from radial move-r drum, a brake shoe for cooperation with the v drum, said shoe comprising an arcuate aveb mounted at one endr on `the support for pivotal movement and for circumferential movement with the drum but restrained from radial movement toward the drum, a lining carrying member extending over at least a portion of the web and having its en'dremote from the mounted end of the web pvotally mounted to said web, and means operable by circumferential mbvement-of the web when the shoe is applied tothe drum for forcing the free' end of the pivotally mounted lining carrying member toward the drum and relatively to the mounted end of the web. f

9. In braking-mechanism, a support, a brake drum, a brake shoe -for cooperation with the drum, said shoe comprising an arcuate web mounted at one-end on the support for pivotal movement and for circumferential movement with the drum, drum engaging means secured to the web over that portion extending froma point intermediate the ends of the web to the free end of theweb, other drum engaging means secured to the web at an intermediate point and extending over and free 'of'the web from said point to the mountedend of the web, and means operable by circumferential movementr'of the web when the #shoe is applied to the drum fox-.forcing the free portion' of the last named drum engaging l means toward the drum. i f

,10. In braking mechanism,` a support, a brake drum, a brake shoe for cooperation th the drum, saidshoe comprisinga member.` ted at one end on the support for pivotalmovement .and for \circumferential movement with the drum, drum engaging means secured to the member at a point spaced from the end and capable of circumferential movement with the K member but freeto move relatively -outward toward the drum over; the portion 'of the 'member between said pointzpf securement and the plv-- oted end of themembenand cooperating cam meanaon means and on the plied.

support for forcing the former toward the drum when the shoe is applied.

. 1l. In braking mechanism, a support, a brake drum, a brake shoe for cooperation'with the drum, said shoe comprising an arcuate web mounted at one end on thesupport for pivotal movement and for circumferential movement withthe drum, a lining carrying ange secured to the web for circumferential movement therewith but free Vof the web for relative outward movement toward thel drum from an intermediate point on the web to the mounted end, and

cooperating cam means carried by the free end of the ange and by the support for forcing said free end toward the drum vwhen the shoe is apl2. In brakingmechanism, a support, a brake drum, a brake shoe for cooperation with the drum,

ythe support for forcing the former toward the drumwhen the shoe is applied to the drum.

13.4 In braking mechanism, a support, a brake drum, a brake shoe for cooperation with the drum, saidl shoe comprising an arcuate web mounted at one endon the support for pivotal movement and for circumferential movementv with the drum, drum engaging means secured to the web over that portion extending from a point intermediate the ends of the' web to the free end of the web, other drum engaging means secured to the web at an intermediate point and extending over the web from said point to the mounted end of theweb and being free of the web exceptvv at the point of securement, and means operable by circumferential movement of the web when the shoeis applied to the drum for forcing4 the free portion of the last named drum engaging means toward the drum, said means comprising a lever having one end pivoted to the support and its other endl cooperating with said last named .drum engaging meansl 14. In braking mechanism, a support, a brake drum, an anchor pin on the support, a brake shoe mounted on the anchor lpin for cooperation with the drum, said shoe comprising `an arcuate web mounted on the pin for pivotal movement and for circumferential, movement withv the drum, drum'engaging' means Isecured to the portion of the'4 web remote from -th'e pivoted end.

other drum engaginglmeans connected at one of itends to an intermediate part of the web and extending over the portion of the web between said lpoint of connection and the pivoted end but free to move relatively to ,the web and outwardly towardthe drum, and means carried by the pin and cooperating with the last named drum engagin'g means and operable by the circumferential` movement of the web whenitheshoe is apmounted on the pin forl pivotal movement and v for circumferential movement? with ythe drum drum` engaging means tov the web at point circumferenuguyspaa from the pivoted plied to the drum for forcingv the last named a brake shoe for cooperation with the vmeans carried .by the pivot pin and provided with a cam surface, and a cooperating cam surface carriedby the free end of the drum'engaging means, said cam surfaces causing the free end of the drum engaging means to be forced outwardly l amate? l carrying portion toward the drum, and a spring for biasing said free part of thelining carrying portion toward the web.

Y 17. In braking mechanism, a support, a brake drum, a brake shoe for cooperationn with -the drum, said shoe comprising an arcuate web mounted at one end of the Support for pivotal toward the drum by a/circumferentiai movement movement and for circumferential movement of of the web when the shoe is applied to the drum. 16. In braking mechanism, a support, a brake drum, said shoe comprising an arcuate web mounted at one end on the support for pivotal movement and for circumferential movement with the drum, a lining carrying portion secured to the web at a pointcircumferentiall'y spaced from the mounted end and free of said web from said point of securement to the mounted end of the web. means operable by circumferential movement ofthe web when the shoe is-applied to the drum for forcing the free part of thelining -the drum, said web having a portion extending from an intermediate point to the mounted end 10 which is free to move'relatively outward toward the drum, a continuous lining/carrying iiange extending over and secured to the web, and means comprising a lever having one end pivotally mounted on the support and the other end coop- 16 eratively engaging the portion of the web that is free to move outwardly toward the drum for forcing the latter and the lining carrying flange secured thereto toward the drum when the shoe is 

